1. Field of the Invention
The present invention relates generally to an internal combustion engine operable with a mixture of air and a fuel such as a hydrocarbon fuel (for example, gasoline) or alchols (for example, methyl alchol) and, more particularly, to a fuel reforming system for converting a rich mixture of air and the fuel into an easily combustible reformed gaseous mixture containing hydrogen and for feeding the reformed gaseous mixture into a combustion chamber of the engine for the combustion therein to thereby reduce the emission of the harmful components of the engine exhaust gases and improve the fuel consumption of the engine.
2. Description of the Prior Art
In order to comply with the requirements for the purification of engine exhaust gases, it has recently been strongly demanded that a mixture of air and a fuel to be supplied into an engine is uniformly distributed to respective cylinders and that the ignitability and combustibility of the mixture in combustion chambers are improved.
In the past, in an attempt to comply with the demands discussed above, there has been proposed an apparatus for heating an intake system of an engine by engine exhaust gases or warmed engine cooling water to facilitate the atomization of fuel in the intake system. With the proposed prior art apparatus, however, the atomization of fuel depends upon the temperature of the engine exhaust gases or cooling water with the resultant disadvantage that it is difficult to obtain sufficient atomization of fuel over all ranges of the operating conditions of the engine. In addition, the prior art apparatus has improved the ignitability and combustibility of fuel only to the extent that is achieved by mere atomization of the fuel and, thus, has not completely satisfied the requirements. References will be made hereunder to examples of the prior art apparatus.
U.S. Pat. No. 1,687,918 issued Oct. 16, 1928 to L. M. Woolson discloses a heater disposed in an intake system of an internal combustion engine downstream of a carburetor to heat an air-fuel mixture produced thereby. The heater includes a sparking plug for igniting and burning a part of a fuel to produce heat which is transferred through a corrugated wall to the air-fuel mixture flowing through an intake pipe from the carburetor. The heater is disposed in the intake system downstream of a throttle valve which is disposed in the intake system downstream of the carburetor. The combustion of the part of the fuel in a combustion chamber of the heater, however, is disadvantageously influenced by the variation in the vacuum produced by the engine in the intake system. In addition, the heater needs secondary air to be mixed with the part of the fuel to be burnt in the combustion chamber of the heater. The flow of the secondary air into the combustion chamber is controlled by a spring controlled automatic valve to control the combustion of the fuel in the combustion chamber.
U.S. Pat. No. 2,401,862 issued June 11, 1946 to J. J. Dugas discloses a fuel heating system intended to adapt a carburetor to use heavy oil. The system comprises a heater which is disposed outside an intake system of an internal combustion engine and in which fuel is burnt to produce combustion gases which are caused to flow first through a first coil of tube disposed in the intake system downstream of the carburetor and then through a second coil of tube disposed in a float chamber. The heat produced by the combustion is utilized merely to reduce the viscosity of the oil in the float chamber and vaporize an air-fuel mixture produced by the carburetor.
U.S. Pat. No. 3,828,736 issued Aug. 13, 1974 to Christian Koch discloses method and apparatus for the combustion of a fuel. By the method, air and engine exhaust gases are mixed with a fuel to form a mixture which is then passed over a catalyst bed so that the mixture is converted into a gaseous mixture of methan and carbon monoxide which mixture is then fed into an internal combustion engine. The apparatus may include ignition means disposed at the inlet portion of the catalyst bed to heat the catalyst.
In general, internal combustion engines need fuels of high octane values in order to produce high output. For this reason, each of the conventionally used fuels contains an appropriate amount of aromatic hydrocarbon and lead compound which are known to produce harmful compounds and thus give rise to environmental pollution. Thus, smooth operation of internal combustion engines with low octane value fuels has long been desired but not yet attained before the present invention.